The invention relates to a medical instrument with a shaft connected proximally to a handle, with an insert guided along the shaft, which insert is connected to a moveable grip part of the handle on the proximal side and distally has a tool which can be actuated by moving the moveable grip part, and with a lock which can lock the moveable grip part in a position.
The lock can fix the moveable grip part that actuates the instrument. The lock usually consists of a rod-shaped component attached to an unmoveable grip part. On the side facing the moveable grip part, the lock has teeth which interact with a latching element on the moveable grip part.
For example, DE 102 32 086 A1 and WO 2006/071120 A1 disclose further instruments with such locks.
Such medical instruments are used particularly in minimally invasive surgery and are continuously developed in respect of use and adjustment options.
By way of example, one development consists of designing the rigid shaft such that it can bend at least in its distal end region.
Such apparatuses are known from e.g. U.S. Pat. Nos. 5,618,294 and 6,077,287. The bendability is achieved by virtue of the fact that the distal end region has a flexible design, for example in the form of elements interconnected in a spine-like fashion. Control, i.e. bending and realigning to a straight line, is brought about by cables arranged diametrically in the shaft.
For this, a number of adjustment members are present in the region of the handle or the grip parts. That is to say, there are adjustment members for deflecting the shaft, adjustment members for moving the grip part, adjustment members for opening and closing the locking function and the like. There is ambition to arrange these adjustment members in the region of the handle where possible such that an operator, who has picked up the instrument by the handle, can operate the various adjustment members using his/her fingers.
However, care has to taken in this case that these adjustment members are arranged as ergonomically as possible and are also unambiguous so that a wrong adjustment member is not inadvertently operated during a surgical intervention.
In the case of combined dissecting/gripping forceps, it is desirable for the jaw parts of the tool to be able to be moved freely for the duration of the dissecting process, i.e. the latter should not be interrupted by an inadvertently triggered other function.
After the dissection, e.g. severing a piece of tissue, it then is desirable for this severed piece of tissue to be held between the jaw parts, with a certain amount of contact pressure and holding pressure having to be exerted and the tissue being intended to be held in this state. This hold should ensure that the held piece of tissue is not lost during further manipulations, but that it can be pulled away from the body during a minimally invasive intervention, for example through a trocar cannula sticking in the body. If, for example, the dissecting process and the subsequent gripping process were carried out in an angled state of the shaft, the latter would firstly have to be aligned in a straight line so that it can be pulled out through a trocar cannula.
Thus, an object of the present invention is to develop a medical instrument, particularly an instrument with a shaft that can be angled, to the end of affording functionally reliable and ergonomic handling, particularly in respect of the locking and the release of the locking of the moveable grip part.